1. Field of the Invention
The present invention relates generally to an access device for a blunt tip cannula. More specifically, the present invention relates to a packaging combination of a blunt tip cannula and access device which maximizes the convenience to the user.
2. Background of the Invention
Medical containers such as medication vials are commonly used to store bulk quantities of medications in a sterile condition prior to use. Most often, these vials allow access to their contents through a septum made of a relatively thick, elastomeric material. The thick septum is designed to be pierceable by a sharp needle to allow access to the vial contents and to reseal after the needle is withdrawn. The thickness of the septum allows it to maintain its integrity even after multiple uses.
Medical tubing, such as IV tubing, often includes injection sites to allow medication or other fluid to be injected into the IV line. These injection sites often include an injection port which is also sealed with a relatively thick elastomeric septum which is intended to be pierced by a sharp needle.
Due to the relative thickness and general manufacturing specifications of these elastomeric septa, they are very difficult to pierce without a piercing element which includes a sharp tip. It is nevertheless becoming increasingly common, due to the problem with the potential spread of disease by accidental sticking with sharp tip needles, for users to attempt piercing septa with cannulas having blunt tips thereon. However, a problem arises when the septa are not pre-pierced. The blunt tip cannulas are not capable of puncturing through the septum material without prior piercing thereof with a sharp needle.
There has therefore existed in the art since the advent of the blunt tip cannula, a need for a device that facilitates penetrating the septum of a vial or an injection port to permit access with a blunt tip cannula.
An early prior art approach to resolving this problem has been to provide a vial adaptor which can be attached directly to the vial in such a way that the adaptor passes through the vial septum and is itself designed to allow a blunt tip cannula to pass therethrough in a facile manner. Examples of this concept have taken several different forms, such as disclosed in U.S. Pat. No. 5,433,330 to Yatsko et al., U.S. Pat. No. 3,940,003 to Larson and U.S. Pat. No. 4,543,101 to Crouch.
Another prior art attempt to solve the problem of accessing a vial or injection port septum with a blunt tip cannula has been to merely pre-pierce the septum to provide a path through which the blunt tip cannula may pass. This has been done by pre-piercing the vial or injection port septum with a sharp pin or needle just prior to penetrating with the blunt tip cannula. However, these solutions have been less than completely desirable. Vial adaptors require additional significant time in setting up or changing over the vial for blunt cannula access. Also, septa pre-pierced at the time of assembly are often difficult to identify visually. Pre-piercing a septum with a sharp needle and syringe just prior to inserting a blunt tip cannula therethrough has the dual draw back of requiring the use of a sharp needle, which is what the blunt tip cannula is designed to avoid, and the added expense of using two needle systems, a sharp tip needle and the blunt tip cannula, to accomplish vial or injection port access.
Finally, another prior art approach utilizes a pointed adaptor provided at the tip of a cannula for piercing the injection port septum. U.S. Pat. Nos. 5,470,351 and 5,580,351, to Helgren et al. disclose a device comprising a blunt tip cannula with a pointed adaptor at the distal end thereof for piercing the septum and subsequently permitting entry of the blunt tip cannula therethrough. However, the pointed adaptor utilized in the Helgren et al. device includes a breakaway collar that leaves the pointed adaptor inside the vial after the septum has been pierced which is undesirable. Therefore, there is a need in the art for providing an access device for piercing the septum of a vial and providing it as part of the packaging of a blunt tip cannula or blunt tip cannula/syringe combination which overcomes the drawbacks of the prior art.